The Tissue Analysis Core (Core B) has a central role in our Program Project. This core will provide essential services for the three projects. The approach of Core B will be multidisciplinary, using classical neuropathological as well as current immunohistochemical and in situ hybridization methods to evaluate mechanisms of ischemic brain injury, and injury associated with experimental autoimmune encephalomyelitis (EAE), an animal model for multiple sclerosis (MS). There are three main aims. In the first aim, the staff of Core B will be responsible for preparing all histologic sections for studies of focal ischemia, including sections processed for infarct volume determination, immunohistochemistry for CART and NeuN proteins, in situ hybridization for CART mRNA , and DNA break staining (TUNEL) in females. In the second aim, the staff of Core B will be responsible for preparing all histological sections for studies of focal ischemia, as well as immunocytochemistry and in situ hybridization for cytochrome P450 aromatase and 5 alpha-reductase in young and middle-aged males. In the third aim,the Tissue Analysis Core will process spinal cord materials in different mouse models of experimental autoimmune encephalomyelitis (EAE), including luxol fast blue-periodic acid Schiff-hematoxylin staining and immunohistochemistry for cells and proteins involved in EAE. The analysis will also include immunoperoxidase stain for amyloid precursor protein as a measure of axonal injury, microtubule- associated protein 2 for dendritic morphology/injury and synaptophysin to evaluate synaptic density. The staff will assist in training personnel from the various Projects in the preparation of tissues and the associated data analysis. The centralization in one laboratory will provide a significant saving in the use of common supplies and reagents for histological analyses, and will also allow the labs to benefit from the expertise of Core B. Most importantly, redundancy in man power and technical time to do general histology, immunocytochemistry and in situ hybridization will be avoided, and the core will ascertain that tissues are processed in a timely fashion. In addition, having a central histology core will foster interactions between the different laboratory groups.